Andrew McCabe, the former acting director of the FBI, revealed he launched counterintelligence and obstruction of justice investigations into President Trump and his possible links to Russia after speaking to the commander-in-chief about his firing of James Comey.

“I was very concerned that I was able to put the Russia case on absolutely solid ground in an indelible fashion that were I removed quickly and reassigned or fired that the case could not be closed or vanish in the night without a trace. I wanted to make sure that our case was on solid ground,” McCabe told CBS’ “60 Minutes” in an excerpt of the interview that will air Sunday.

“And if somebody came in behind me and closed it and tried to walk away from it, they would not be able to do that without creating a record of why they’d made that decision,” he said in the snippet released Thursday.

McCabe said he was “troubled” by the conversation he had with Trump.

“I was speaking to the man who had just run for the presidency and won the election for the presidency and who might have done so with the aid of the government of Russia, our most formidable adversary on the world stage. And that was something that troubled me greatly,” said McCabe, who was named acting director after Trump fired Comey in May 2017.

The next day, he launched the probes.

“I met with the team investigating the Russia cases. And I asked the team to go back and conduct an assessment to determine where are we with these efforts and what steps do we need to take going forward,” he said.